Vehicle braking systems

ABSTRACT

A control valve arrangement particularly for use in a vehicle braking system having fluid pressure brake actuator means and fluid pressure controlled lock actuator means, comprises two separate control valves operated by a single control lever, and a gate which governs movement of the control lever has two parallel legs and two parallel cross-paths intersecting the legs. Mechanical one-way latching means co-ordinate control of the respective valve in such a manner that the lock actuator is rendered operative and inoperative only at predetermined pressure values of the brake actuator means.

United States Patent Hughes 1 VEHICLE BRAKING SYSTEMS [75] Inventor:Michael James Hughes, Tyseley,

England [73] Assignee: Girling Limited, Birmingham,

England [22] Filed: Mar. 31, 1972 211 Appl. No.: 240,117

[30] Foreign Application Priority Data Apr. 2, 1971 Great Britain8,552/71 [52] US. Cl. 303/89, 74/476 [51] Int. Cl B60! 7/08 [58] Fieldof Search 303/7, 9, 13, 52, 303/54, 89; 74/473, 475, 476, 471 XY;188/265 56] References Cited UNITED STATES PATENTS 3,586,392 6/1971Ballard et aL 303/89 2,273,068 2/1942 Ross et al. 74/473 Dec. 18, 1973,

Coldwell 74/476 Robinson et a1 74/476 Primary Examiner-Milt0n BuchlerAssistant Examiner-Charles E. Frankfort Artorney-Samuel Scrivener, Jr.et al.

[5 7 ABSTRACT A control valve arrangement particularly for use in avehicle braking system having fluid pressure brake actuator means andfluid pressure controlled lock actuator means, comprises two separatecontrol valves operated by a single control lever, and a gate whichgoverns movement of the control lever has two parallel legs and twoparallel cross-paths intersecting the legs. Mechanical one-way latchingmeans co-ordinate control of the respective valve in such a manner thatthe lock actuator is rendered operative and inoperative only atpredetermined pressure values of the brake actuator means.

3 Claims, 2 Drawing Figures 1 VEHlCLE BRAKING SYSTEMS This inventionrelates to control valve means particularly suitable for use in fluidpressure braking systems in which fluid pressures are suppliedseparately to a service brake actuator (such as a wheel cylinder) and toa lock unit for holding the brake applied mechanically and having afluid pressure motor for releasing the lock. Such an arrangement isdescribed, for example in the complete specification of our co-pendingPatent application No. 54114/68. 1f the lock unit comprises resilientmeans for protecting the lock against mechanical overload in the appliedcondition, it is desirable to protect the resilient means themselvesagainst excessive deflection and loading, and the present invention isconcerned with a gate type of control valve arrangement for thispurpose.

In accordance with the present invention, there is provided a fluidpressure control valve means comprising two separate control valves forregulating the pressure in separate pressure systems, a common operatinglever for controlling the respective valves by movements in two mutuallytransverse directions and a gate constraining movements of the lever,wherein the gate has a first and second parallel legs, movement of thelever alone either of which varies the setting of one control valve, andfirst and second cross-paths transverse to and intersecting the twolegs, movement of the lever along either of which cross-paths varies thesetting of the other control valve, and one-way latching meanspositioned to prevent movement of the lever from one end of the secondleg into the first leg except dance with the invention is describedbelow, by way of 5 example, with reference to the accompanying drawings,in which:

FIG. 1 is a perspective view of the control valve arrangement; and

FIG. 2 is a diagrammatic view of the gate and latching means.

The control valve arrangement comprises two separate control valves 10and 11 arranged to be operated by a common control lever 12, movement ofwhich is constrained by a gate 13. The gate restricts movement of thelever to movements in two mutually transverse directions, movement inone direction varying the setting of valve 10 between zero pressure anda maximum pressure and movement in the other direction opening andclosing the control valve 11. The valves are of any suitable type knownper se, each being responsive to an angular or a rectilineardisplacement of its actuating member.

In use, control valve 10 is connected in a pressure line between apressure source and a brake actuator, such as a wheel brake cylinder,and valve 11 between a pressure source and a lock actuator unit.

Referring now to FIG Z, movement along a main leg 1 from 1 A to Ceffects a progressive pressure rise through the actuator control valve10 from zero to the maximum available pressure, say 2,000 p.s.i. Asecond parallel leg 2 controls a pressure range from zero at E to apressure below the maximum, say 1,760 p.s.i. at D.

Pressure through the lock unit control valve 1 1 is varied by movementof the control lever along either of two parallel cross paths 3 and 4,from zero at D and F, to predetermined maximum pressure at B and G.Mechanical one-waylatching devices 5 and 6 are included at F and G, sothat the control lever can only be moved to relieve the lock motorpressure along the path B,D at an actuator pressure of 1,760 p.s.i. andlock motor pressure is restored by movement of the lever from F to E, atan actuator pressure of 1,300 p.s.i. Each latching means convenientlycomprises a swinging arm lightly spring biased against a stop so as toextend across the respective leg or cross-path of the gate. The latch isreadily swung away from the stop when engaged by the lever 12 from oneside, but blocks the lever against movement in the opposite direction.

In use, the control lever is normally at point A, so that the lock motoris pressurised to prevent the lock from coming into operation. To parkthe vehicle, the lever is moved to point B, to apply 1,760 p.s.i. to theactuator, and then to D to exhaust the lockmotor. The actuator pressureis then relieved by moving the lever from D to E. Due to relaxation inthe lock mechanism, the effective load exerted by the lock unit is justless than that corresponding to an actuator pressure of 1,300 p.s.i. butin excess of the initial pre-load of the resilient means of the lockunit. To release the lock, the lever is moved from E to F, (where it ischecked by the non-return gate), thus supplying pressure at 1,300 p.s.i.to the actuator to relieve the lock of load, and then from F to G torestore normal operating pressure to the lock motor, releasing the lock.

The non-return gate at G thus prevents a parking operation withinsufficient parking brake effort.

I claim:

1. Fluid pressure control valve means comprising two separate controlvalves for regulating the pressure in separate pressure systems, acommon operating lever operatively coupled to the said valves forcontrolling the same by movements in two mutually transverse directions,a gate constraining movements of said lever, said gate having first andsecond parallel legs, movement of said lever along either of whichvaries the operative setting of one said valve, and first and secondcrosspaths transverse to and intersecting said first and second legs,one of said crosspaths being intermediate the ends of said legs,movement of said lever along either of said crosspaths being operativeto vary the operative setting of the other of said valves, andmechanical one-way latching means constructed and arranged that whensaid lever is at the end of a selected one of said legs which end isnearest the intermediate crosspath said lever is prevented from movementto the other leg except through said intermediate cross-path.

2. The control valve means of claim 1 including second mechanicalone-way latching means constructed and arranged so that when said leveris in said other leg it is prevented from movement into said first legexcept through the other of said cross-paths.

3. Control valve means as claimed in claim 2, in combination with avehicle braking system comprising first gate and said first and secondlatching means permit said lock actuator to be applied only at apredetermined higlnpressure and to be released only at a predeterminedlower pressure.

1. Fluid pressure control valve means comprising two separate controlvalves for regulating the pressure in separate pressure systems, acommon operating lever operatively coupled to the said valves forcontrolling the same by movements in two mutually transverse directions,a gate constraining movements of said lever, said gate having first andsecond parallel legs, movement of said lever along either of whichvaries the operative setting of one said valve, and first and secondcrosspaths transverse to and intersecting said first and second legs,one of said crosspaths being intermediate the ends of said legs,movement of said lever along either of said crosspaths being operativeto vary the operative setting of the other of said valves, andmechanical one-way latching means constructed and arranged that whensaid lever is at the end of a selected one of said legs which end isnearest the intermediate crosspath said lever is prevented from movementto the other leg except through said intermediate cross-path.
 2. Thecontrol valve means of claim 1 including second mechanical one-waylatching means constructed and arranged so that when said lever is insaid other leg it is prevented from movement into said first leg exceptthrough the other of said cross-paths.
 3. Control valve means as claimedin claim 2, in combination with a vehicle braking system comprisingfirst and second pressure paths, a brake actuator in said first path anda lock actuator unit in said second path, said separator control valvesbeing positioned in said first and second pressure path, respectively,whereby said gate and said first and second latching means permit saidlock actuator to be applied only at a predetermined high pressure and tobe released only at a predetermined lower pressure.